South London Clays and Gravels
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17. South London Clays & Gravels Key plan Description The South London Clays and Gravels is an extensive Natural Landscape Area that incorporates parts of 9 boroughs - Kingston, Sutton, Merton, Wandsworth, Croydon, Lambeth, Bromley, Southwark & Lewisham. It extends south and west from Deptford towards Streatham and New Malden. It is bordered by two river systems, the Wandle (NLA 16) and the Ravensbourne (NLA 8) to the east and west, and by the North Downs Lower Dip Slope (NLA 21) to the south. The whole area is underlain by London Clay, but in places (Crystal Palace and Chessington) the Clay is capped by the younger, more resistant strata of the Claygate Member to form ridges. At Crystal Palace the ridge is particularly prominent and extends north–south from Forest Hill to Upper Norwood, with superb views across to the Isle of Dogs and the City and, to the south, to Croydon and the North 17. South London Clays & Gravels Downs. To the south of this ridge, the older rocks of the Harwich Formation (pebbly beds) and the gravelly sands and clays of the Lambeth Group crop out in the Thornton Heath and Carshalton areas. This out crop does not correspond to an obvious variation in landform, but the sandy soils associated with the Lambeth Group tend to support heathland and this is also suggested by some local place names. The oldest rocks are in the Deptford area to the north, where an exposure of the Thanet Sand Formation and small inliers of Lewes ENGLAND 100046223 2009 RESERVED ALL RIGHTS NATURAL CROWN COPYRIGHT. © OS BASE MAP Nodular Chalk Formation are surrounded by sands/gravels from the 17. South London Clays & Gravels Lambeth Group. Again there is no significant change in landform, but the extensive gravel deposits here, and also in the Clapham/Tooting areas to the west, moved downslope by hill wash and solifluction processes, depositing Head alongside the flooded river corridors of the Thames and the Wandle, generally as a result of melting permafrost. 98 London’s Natural Signatures: The London Regional Landscape Framework / April 2010 Alan Baxter REPRODUCED FROM THE BRITISH GEOLOGICAL SURVEY MAP DATA AT THE ORIGINAL SCALE OF 1:50,000. AT SURVEY DATA MAP THE BRITISH GEOLOGICAL REPRODUCED FROM RESERVED. © NERC. ALL RIGHTS SURVEY. LICENSE 2006/072J BRITISH GEOLOGICAL ACKNOWLEDGEMENT: ENGLISH HERITAGE DATA ENGLISH HERITAGE ACKNOWLEDGEMENT: © OS BASE MAP CROWN COPYRIGHT. ALL RIGHTS RESERVED NATURAL ENGLAND 100046223 2009 RESERVED ALL RIGHTS NATURAL CROWN COPYRIGHT. © OS BASE MAP DATA ENVIRONMENT AGENCY ACKNOWLEDGEMENT: Geology Rivers and Topography Historic Development The settlement pattern is varied, ranging from open countryside and farmland in the south west to dense residential, industrial and commercial developments to the north and east. The two oldest key settlement cores are at Croydon and South Clapham. Elsewhere most built development dates from the Victorian period and the boom in residential development which followed the growth of the railways, although south of Peckham Rye, extending to Streatham Vale, the housing stock is predominantly interwar suburbia. There are high 17. South London Clays & Gravels rise tower buildings in areas that suffered particularly heavy bomb damage in the Second World War and a particularly dense complex of sewage works and heavy industry at Beddington. Whilst the Malden Ruston area to the south west is surrounded by open countryside and farmland, the majority of the landscape type is densely developed, and the open space matrix consists of a fragmented network of historic commons, public parks, playing fields and golf courses maintained as amenity grassland. There are also fragmented small patches of native woodland and hedgerows, typically along railway sidings and in some parks. Alan Baxter London’s Natural Signatures: The London Regional Landscape Framework / April 2010 99 Natural Signature and natural landscape features Natural Stignature: Burgess Park South London Clays and Gravels – Small hedged meadows and large heathy commons set against a backdrop of extensive Clapham Brockwell woodlands on higher land. Common Park Wandsworth The Great North Wood was an exceptionally dense forest, recorded Balham Common Railway in the Domesday Book, which once extended from Selhurst/Elmers Embankments End northwards towards what is now Upper Norwood, Forest Hill Tooting Dulwich & Common and Hatcham/Deptford. By the 17th century significant parts of it Sydenham Hill Woods were Common Land, and little now remains, but fragments of ancient woodland on higher land provide core areas of valuable habitat which could be a priority for future woodland planting. The network of woodlands, hedgerows, small meadows and field ponds at Tolworth Court Farm Fields indicates the likely scale and character of farmland surrounding the woodlands and the floodplain meadows and woodlands in the Hogsmill Valley Nature Reserve suggests how the South Norwood Mitcham Country Park landscape pattern would have varied along river valleys. Common This is obviously a snapshot in time, but it suggests the character Hogsmill River Valley of the rural landscape during the period before urbanisation and it Morden Cemetery provides a set of references to inform the Natural Signature of this Tolworth Court Farm extensive area. Fields & Medieval Examples of natural landscape features within the South London Clays Moated and Gravels Natural Landscape Area are: Manor • Dulwich and Sydenham Hill Woods – The largest remnant of the historic Great North Wood and one of the closest ancient woodland The to central London. Mostly sessile oak-hornbeam woodland, with a Meadowlands wide variety of other tree and shrub species, including numerous Rushett 17. South London Clays & Gravels exotics planted when the wood included parts of large gardens. The Common flora includes numerous indicators of long-established woodland; wood anemone, lily-of-the-valley and hairy wood-rush. Two ponds contain aquatic vegetation and support amphibians and ENGLAND 100046223 2009 RESERVED ALL RIGHTS NATURAL CROWN COPYRIGHT. © OS BASE MAP GIGL DATA ACKNOWLEDGEMENT: dragonflies. Natural Habitats & Landscape Key Features 100 London’s Natural Signatures: The London Regional Landscape Framework / April 2010 Alan Baxter • Hogsmill Valley – This Local Nature Reserve encompasses the • Morden Cemetery – This cemetery contains areas of flower-rich entire Hogsmill river corridor from Berrylands rail station south neutral grassland, very rare in London and once supporting the only to Malden Lane, comprising a varied mosaic of relict floodplain colony of green-winged orchid in London. habitats. The majority of the valley is open species-rich grassland, but there are also small pockets of willow woodland over sedge • Rushett Common – This site includes two tracts of woodland beds, which support one of London’s few populations of slender alongside the A243 from Malden Rushett south to London’s tufted-sedge. The Hogsmill, a chalk stream, has a diverse aquatic boundary with Surrey. The woodland consists mostly of flora here including horned pondweed and a well established fish pedunculate and sessile oaks, with yellow archangel and woodruff community. The specially protected water vole is also present. in the ground flora. West of the road, the site also includes areas of scrub and grassland, with common gorse and heath bedstraw. • Tolworth Court Farm Fields and Medieval Moated Manor – A large area of farmland, with a field system of pastures, hedgerows • Mitcham Common – A large common consisting mainly of and woodland. The site also includes the remains of a medieval acid grassland and secondary woodland, with some interesting moated manor house, where there are important wetland habitats. wetlands and several small but important areas of heathland. The This large area of relict farmland comprises a field system of both heath communities are degraded but notable for the abundance grazed and ungrazed pastures, hedgerows and small blocks of of the London rarity dwarf gorse, marking them as intermediate secondary woodland. There are varied examples of grassland in composition between the heathlands of East Anglia and central management, with some fields retaining species indicative of old southern England. hay meadows and damper fields supporting dense rush beds. The • Balham Railway Embankments – The Wandsworth area has a hedge network is very old, with several veteran oak pollards present. particularly complex criss-crossing network of railways, partly due to Several small areas of woodland have developed from these the location of Clapham Junction. This adds up to a substantial area hedgerows, and consist predominantly of oak and elm. The ancient of natural habitat and provides important wildlife corridors linking trackway of Cox Lane traverses the site, adding further historical the various commons and major wildlife sites together. Much of the interest. The remains of the moat form a large overgrown pond, habitat is a mix of native and non-native broadleaved woodland overhung by willows and other wetland plants. and roughland, with frequent patches of regenerating elm scrub • The Meadowlands – A small area of species-rich chalk grassland and bracken. The embankments either side of Balham station are preserved within a housing estate. The turf supports an covered in dense scrub, mostly of bramble with stands of tall herbs extraordinary diversity of plants, including bee and pyramidal and coppiced sycamore. orchid. 17. South London Clays & Gravels Alan Baxter London’s